Test arrangement for testing high-frequency components, particularly silicon photonics devices under test

ABSTRACT

The invention relates to a probe card (PC) for use with an automatic test equipment (ATE), wherein the probe card (PC) comprises a probe head (PH) on a first side thereof, and wherein the probe card (PC) is adapted to be attached to an interface (IF) and wherein the probe card (PC) comprises a plurality of contact pads on a second side in a region opposing at least a region of the interface (IF), arranged to contact a plurality of contacts of the interface (IF), and wherein the probe card (PC) comprises one or more coaxial connectors (CCPT) arranged to mate with one or more corresponding coaxial connectors (CCPT) of the interface (IF). The invention relates further to pogo tower (PT) for connecting a wafer probe interface (WPI) of an automatic test equipment with the probe card (PC).

RELATED APPLICATION(S)

The present Applications is a Continuation of PCT Application NumberPCT/EP2020/058634, filed Mar. 26, 2020, which is incorporated herein byreference in its entirety.

DESCRIPTION Technical Field

Embodiments according to the invention relate to a probe card for usewith an automatic test equipment, a pogo tower for connecting a waferprobe interface of the automatic test equipment with a probe card, theautomatic test equipment and a method for testing a device under testusing said automatic test equipment.

Background of the Invention

Automatic test equipment is widely used in the electronic manufacturingindustry to test electronic components and systems after beingfabricated. The device being tested is known as a device under test.Automatic test equipment quickly performs measurements and evaluates thetest results. This is specifically necessary in the semiconductorindustry where automatic test equipment can test a wide range ofelectronic devices and systems from single components to complex andcompletely assembled electronic systems. For such a purpose, probe cardsare used. Automatic test equipment systems are designed to reduce theamount of test time needed to verify that a particular device under testworks or to quickly find its faults before the part has a chance to beused in a final consumer product. Therefore, to reduce manufacturingcosts and improve yield, semiconductor devices should be tested afterbeing fabricated to prevent defective devices ending up with theconsumer. Conventional automatic test equipment consists of a mastercontroller—usually a computer—that synchronizes one or more source- andcapture-instruments while the device under test is physically connectedto the automatic test equipment using another device called a handler ora prober having a customized interface that adapts the automatic testequipment resources to the device under test. The automatic testequipment can be used on packaged parts—typical integrated circuit‘chip’—or directly on a silicon wafer. Packaged parts use a handler toplace the device on a customized interface board, whereas silicon wafersare tested directly with high precision probes. The automatic testequipment systems interact with the handler or prober to test the deviceunder test.

Devices under test can be highly complex setting challenging standardsto automatic test equipment. Testing a device for all parameters may ormay not be required depending on the device functionality and end user.For example, if the device finds application in medical or life-savingproducts then many of its parameters must be tested, and some of theparameters must be guaranteed. Specifically, photonic chips or hybridsthereof represent a particular challenge, since testinghigh-speed/high-frequency pins of a silicon photonics device under testat a wafer testing level in a high-volume production is only possible inseparate process steps using different testing devices. A big challengeis testing a die's electrical and photonics side simultaneously.Different solutions have been developed to test silicon photonics chipsbut do not allow for testing high-speed/high-frequency pins of a siliconphotonic part of a device under test in a reliable manner, since afailure coverage is very limited especially on the modulator part of thePhotonics Circuit.

Therefore, it is desirable to provide a concept for reliable testinghigh-speed digital/high-frequency pins of a photonics device under testat wafer level in a high-volume production test cell.

This is achieved by the subject-matter of the independent claims of thepresent application, implying a high-volume production test cell using astandard wafer tower setup and allowing at the same time to test thestandard digital/power pins as well as the photonic pins using forexample a fiber array.

Further embodiments according to the invention are defined by thesubject-matter of the claims of the present application.

SUMMARY OF THE INVENTION

A solution for the wafer probing test fixture design is to connect thewafer probe interface directly to a test fixture.

An aspect according to this invention is related to a probe card for usewith an automatic test equipment, wherein the probe card comprises aprobe head on a first side thereof, for example, for contacting a deviceunder test, i.e. a photonic chip or hybrid thereof, and wherein theprobe card is adapted to be attached to an interface. The interface maybe attached mechanically and/or electrically to the automatic testequipment or segments thereof—directly and indirectly. The probe cardcomprises a plurality of contact pads on a second side averted to thefirst side thereof in a region opposing at least a region of theinterface, arranged to contact a plurality of contacts of the interface.The plurality of contacts of the interface can be, for instance,spring-loaded pins, in other words so-called pogo pins. Above that, theprobe card comprises one or more coaxial connectors arranged to matewith one or more corresponding coaxial connectors of the interface, e.g.an automatic test equipment, in a region opposing at least another ofthe automatic test equipment segments or of coaxial cables forestablishing a connection/communication with one or more high-frequencyinstruments. Main advantages of this approach is increased spaceavailable for items like relay or support circuitry, improved bandwidth,and the overall setup is closer to the final test fixture design, forexample a packaged device under test

Another aspect of the invention is a pogo tower for connecting a waferprobe interface of an automatic test equipment with a probe card,wherein the pogo tower comprises a plurality of pogo tower segments. Thesegments provide space for different measurement equipment, for exampleoptical, analog and digital signals and/or free—cutout—regions. At leastone of the pogo tower segments comprises one or more coaxial connectorsarranged to connect the probe card with one or more coaxial cables forestablishing a connection/communication with one or more instruments,for instance high-frequency instruments, on a side facing the probe cardand at least another one of the pogo tower segments comprises aplurality of pogo pin contacts arranged to contact the probe card withthe wafer probe interface.

This alternative test fixture of a wafer probing is typically composedof three elements. A wafer probe interface connects the automatic testequipment pin electronics—pogo pins—to a probe pogo tower. The pogotower connects the wafer probe interface to a probe card. The probe cardis a wafer probe interface board that contains the probes which connectto the device under test usually positioned on the center of the probinginterface. This type of configuration can typically accommodate a newapplication or device with just the redesign of the probe card. Thewafer probe interface in the pogo tower are normally applicationindependent and designed by the automatic test equipment manufacturersince they are only dependent on the specifics of the automatic testequipment platform.

Another aspect of the invention is an automatic test equipment fortesting/measuring a device under test, which comprises one or morelow-speed signaling components and/or one or more high/speed signalingcomponents enabling it to test/measure photonic chips or hybrids thereofbut also conventional semiconductor integrated circuits. The automatictest equipment comprises:

a pogo tower comprising [the] features corresponding to theabove-described pogo tower for connecting a wafer probe interface of anautomatic test equipment with a probe card comprising [the] featurescorresponding to the above-described probe card;

one or more instruments, for example high-frequency instruments, forgenerating and/or receiving high-frequency signals and/or high-speeddigital signals using one or more coaxial connectors of the pogo towerand/or one or more coaxial connectors of the probe card; one or moreinstruments, for example low-frequency instruments, and/or one or morepower supplies configured to be coupled to the device under test viapogo pins of the pogo tower into contact pads of the probe card forexchanging low-frequency and/or low-speed digital signals;one or more optical instruments, e.g. lasers and/or optical powermeters, connected to one or more optical guides like fiber cables,attached thereto, anda positioning apparatus for establishing an optical coupling between theone or more optical instruments and the device under test, for examplevia the one or more optical guides.

According to an embodiment of the automatic test equipment each—one—ofthe wafer probe interface(s) of the automatic test equipment and/or thepogo tower and the probe card respectively have a recess region, whereinthe recess regions are alignable—even aligned—with each other at leastin a common partial area, whereby the recess regions allow foraccommodation of the positioning apparatus in a space defined by thecommon partial areas. In other words, a common overlap area of thealigned recess regions defines the size of a reception area of thepositioning apparatus.

According to an embodiment, the common partial area of the recessregions extends at least two a location adjacent to the device undertest. A reception area extending adjacent to the device under testallows test equipment and probes to access or be positioned close to thedevice under test in order to directly measure/test minimizingtransmission losses and time in order to allow the secure couplingbetween the device under test and probe/testing devices.

According to an embodiment, the positioning apparatus comprises amovable cantilever arm. The movable cantilever arm can be adjusted tosecurely couple the probe/testing devices like probes, probe head of aprobe card and/or connectors with the device under test. Above that,different probes can be added throughout the testing/measuring of thedevice under test enabling for additional measurements and/or testing ifor when required. The cantilever arm is configured to fully exploit alldegrees of freedom of movement in order to establish a reliableconnection between the automatic test equipment and the device undertest.

According to an embodiment, the movable cantilever arm of thepositioning apparatus extends at least to a location adjacent to thedevice under test. In order to benefit the advantages of short anddirect connections/communication, additional functional flexibility canbe achieved by enabling the cantilever to access and couple with thedevice under test in a secure and easy way.

According to an embodiment, the high-speed signaling instruments allowfor signals with a frequency in a range of at least 25 GHz particularlypreferred up to at least 70 GHz. High-speed signaling instruments whichcover this bandwidth can be used for measuring and/or testing optical orphotonics chips among others and/or conventional chips.

A particular advantage of using a cantilever for accessing high-speedconnectors/connections of a device under test is to be able to testelectrical and photonic parts of a die in quick succession one afteranother and/or simultaneously, since an alignment of the fiber array canbe done fast so as to minimize test time.

Therefore, according to another embodiment, the device under test is asilicon photonics device or conventional semiconductor integratedcircuit or hybrid between a silicon photonics device and a conventionalsemiconductor integrated circuit.

According to an embodiment, the wafer probe interface has a void—hole—ina region facing the pogo tower or the probe card for passing cablesthrough. The void allows, for example, passing through coaxial cables,which can be attached to coaxial connectors of a high-frequencyinstrument.

According to an embodiment, one or more coaxial connectors areconfigured for blind-mating. For example, the connectors can haveplugging receptacles with two side guideposts that are able to handlegreater misalignment thereby ensuring a secure coupling/contact.

According to an embodiment, the coaxial cables protrude from the pogotower or the probe card in a region facing the wafer probe interface.The specific arrangement allows a connection to a pogo tower or a directconnection with the wafer probe interface, whereby intermediatecontacts—needed in case of an intermediary pogo tower—are bridged. Abovethat, the arrangement of the coaxial cables allows a connection toexternal test devices which can be added independently and separatelyfrom the automatic test equipment for complementary testing and/ormeasuring.

According to an embodiment, [the] pogo pins are non-core actual pogopins. The use of coaxial pogo pins allows for a higher packaging densityof the pogo pins and thus, for a higher measuring/data density.Therefore, exclusively non-coaxial pogo pins are used according to anembodiment of the pogo tower.

According to an embodiment, the automatic test equipment has a firstoperation mode configured to test one or more components of the deviceunder test in a sequential/successive mode, and/or a second operationmode configured to test one or more components of the device under testin a simultaneous mode. In other words, the automatic test equipment isconfigured to test one or more low-speed signaling components and/or oneor more high-speed signaling components according to a first operationmode and/or a second operation mode, thus being very flexible in use.

Another aspect of the invention relates to a method for testing thedevice under test using an automatic test equipment comprising thefeatures of the automatic test equipment previously described, whereinthe automatic test equipment applies either one of the following signalsto one or more components of the device under test:

one or more low-speed signals, or

one or more high-speed signals, or

sequentially/successively one or more low-speed signals and one or morehigh-speed signals or vice versa, or

simultaneously one or more low-speed signals and one or more high-speedsignals.

The method allows for testing/measuring devices under test comprisingconventional semiconductor integrated circuits or silicon photonicsdevices or hybrids between a silicon photonics device and a conventionalsemiconductor integrated circuit.

Above that, an idea of the invention is an efficient use of conventionaltest equipment proposing a way to include high-speed/high-frequency pinsto test silicon photonics integrated circuits while being fullycompatible with, for example, a standard production pogo tower or awafer probing setup fixture. Thereby, a testing/measurement ofhigh-speed/high-frequency pins of a silicon photonics device under testat a wafer testing level in high volume production is made possibleallowing for signals with a frequency in a range of at least 25 GHz andup to a frequency range of 70 GHz or above. Above that, the inventionallows to test such pins still using a standard automatic test equipmentpogo tower setup without major modification.

The probe card, pogo tower, automatic test equipment, and method fortesting a device under test as described above are based on the sameconsiderations, as they share the same or similar features which can beused alternatively or additionally. Therefore, for example, the methodfor testing a device under test can be completed with all features andfunctionalities, which are also described with regard to the probe card,pogo tower, or automatic test equipment for testing the device undertest.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are not necessarily to scale; emphasis instead is generallyplaced upon illustration of the principles of the invention. In thefollowing description, various embodiments of the invention aredescribed with reference to the following drawings in which:

FIG. 1 shows an exploded view of a test fixture setup comprising aprobe-card, pogo tower and a wafer probe interface according to anembodiment of the present invention;

FIG. 2 shows a cross-sectional view of the test fixture setup accordingto the embodiment of FIG. 1 as assembled;

FIG. 3 shows a top view of a pogo tower with a wafer probe interface WPIaccording to an embodiment of the present invention;

FIG. 4 shows a bottom view of a pogo tower with a connected wafer probeinterface according to the embodiment shown in FIG. 3 ;

FIG. 5 shows a coupler for coaxial connectors which is configured tomate with corresponding contacts of a socket slot SS of a pogo toweraccording to an embodiment of the present invention;

FIG. 6 shows a perspective view a test cell using a wafer probeinterface and a pogo tower according to an embodiment of the presentinvention;

FIG. 7 shows another perspective view of the test cell according to theembodiment of FIG. 6 .

DETAILED DESCRIPTION OF THE EMBODIMENTS

Equal or equivalent elements or elements with equal or equivalentfunctionality are denoted in the following description by equal orequivalent reference numerals even if occurring in different figures.

In the following description, a plurality of details is set forth toprovide a more thorough explanation of embodiments of the presentinvention. However, it will be apparent to those skilled in the art thatembodiments of the present invention may be practiced without thesespecific details. In other instances, well-known structures and devicesare shown in block diagram form rather than in detail in order to avoidobscuring embodiments of the present invention. In addition, features ofthe different embodiments described herein after may be combined witheach other, unless specifically noted otherwise.

According to FIG. 1 , an exploded view of a typical test fixture setupcomprising a probe card 100, pogo tower 160 and the wafer probeinterface of 190 according to an embodiment of the present invention.The wafer probe interface 190 is configured to connect the automatictest equipment electronics to the probe pogo tower 160. The probe card100 contains the probes which connect to the device under test DUT onthe center of the probe card 100. In the example shown in FIG. 1 , theprobes are concentrated on a small area of a probe head 110. Both thepogo tower 160 and the probe card 100 are manufactured as printedcircuit boards or comprise at least a printed circuit board. This typeof configuration can typically accommodate every new application ordevice with just a redesign of the probe card 100. The wafer probeinterface 190 and the pogo tower 160 are normally applicationindependent and designed by the automatic test equipment manufacturerssince they are only dependent on specifics of the automatic testequipment platform. FIG. 1 shows an example of a vertical probe card 100for a high-speed digital application.

The probe card 100 according to FIG. 1 comprises a probe head 110 on afirst side thereof for contacting a device under test DUT, specificallyphotonic chips or hybrids thereof. The probe card 100 comprises furthera plurality of contact pads—not shown—on a second side thereof beingaverted to the first side (facing away from it). The plurality ofcontact pads is adapted to be contacted or connected to an opposinginterface of the pogo tower 160 in at least a/one region or area thereofby coupling the contact pads with contacts or connectors of the pogotower 160, for example, pogo pins PP. In addition, the probe card 100comprises one or more coaxial connectors 120 (FIGS. 2, 5 ) arranged tomate with one or more corresponding coaxial connectors of pogo tower160, in a region opposing at least another of the automatic testequipment segments or of coaxial cables or coaxial connectors 120 forestablishing a connection/communication with one or more instruments,for example, high-frequency instruments.

The contact pads as well as the coaxial connectors 120 are arranged inseparate segments of the probe card 100, e.g., probe card segments 101,102, 103, 104. According to an embodiment, there are provided individualprobe card segments PCS for different contacts, i.e., pogo pins 165and/or power supplies connectors 170 and/or coaxial connectors 175. Thepower supply connectors 170 may be pogo pins or other power-supply typeconnectors, in some embodiments. By selective separation of thedifferent contacts and coaxial connectors 175 in individual probe cardsegments PCS, their mutual influence of different signals can bereduced.

The interface IF of the probe card 100 is adapted to be attachedmechanically and/or electrically to the pogo tower 160 or an automatictest equipment ATE. According to an embodiment, the interface IF towhich the probe card 100 is attachable is a pogo tower 160, whichrepresents a critical path of a signal from the probe card 100 to thewafer probe interface 190 of the automatic test equipment ATE. Sometimesthe pogo tower 100 is referred to as a spring probe tower comprisingmultiple pogo pins PP. The pogo tower 100 also comprises a plurality ofpogo tower segments, e.g., 161, 162, 163, 164, which are designed tocorrespond in a complementary way to at least one or more probe cardsegments, e.g., 101, 102, 103, 104, of the probe card 100. The differentprobe card segments 101-104 as well as the corresponding pogo towersegments 161-164 enable flexibly adaptable solutions and products.

The embodiment according to FIG. 1 shows a probe card 100 and the pogotower 160 having dedicated probe card segments 161-164 and dedicatedpogo tower segments 161-164 for low-frequency signaling connections likea plurality of pogo pins, and high-frequency signaling connections likecoaxial cables with coaxial connectors 120 (FIG. 2 ) and 175, as well asa segment defining a recess region or void 180. One or more coaxialconnectors 175 within socket slot 111 (see also item 210 of FIG. 2 ) areadapted to connect the probe card 100 with one or more coaxial cablesfor establishing a connection/communication with one or morehigh-frequency instruments. The high-frequency instruments are adaptedfor generating and/or receiving high-frequency signals and/or high-speeddigital signals using one or more coaxial cables connected to thecoaxial connectors 175 of the pogo tower 160, and/or one or more coaxialconnectors of the probe card 100 which are located in the interfaceIF—not shown. The high-speed signaling instruments allow for signalswith a frequency in the range of at least 25 GHz, particularly preferredup to at least 70 GHz.

Pogo pins PP are spring pin contacts which cover a widehigh-bandwidth-range with high compliance. Nevertheless, their use isrestricted in case of high-speed digital signals or high-frequencysignals beyond 5 GHz. In order to avoid the misalignment of thehigh-frequency/high-speed digital contacts, one or more coaxialconnectors 120/175 are configured for blind mating, whereby pluggingreceptacles have two side guideposts. For the particular purpose toconnect an optical fiber OF to a silicon die optical waveguide coupler,like on-chip grating coupler for vertical coupling, V-groove coupling,and edge-coupled optical fiber OF to on-chip waveguides are used.Dependent on the requirements of the tests and measurements, multiplelaser sources can be used to provide different signaling. The opticalside requires the fiber array to be aligned with precision on top of thegrating coupler and the alignment of the fiber array needs to be done asfast as possible to minimize test time. According to one embodiment—notshown—the probe card uses standard wafer prober auto-loading.

Also, low-frequency instruments and/or one or more power supplies PS areconfigured to be coupled to the device under test DUT via pogo pins 165,170 of the pogo tower 160 and the contact pads of the probe card 100 forexchanging low-frequency, direct current, and/or low-speed digitalsignals. The segments having the recess region 181 of the probe card 100and/or recess region 180 of the pogo tower 180 respectively, define whenproperly aligned in at least one common partial area thereof a freespace, which permits the reception of a positioning apparatus (notshown, see item 610 of FIG. 6 ). The positioning apparatus PA isprovided for establishing an optical coupling between one or moreoptical instruments and the device under test DUT, for example, via oneor more optical guides—see FIG. 6, 7 for example optical fiber OFcables. The optical guides connect one or more optical instruments, forinstance, lasers and/or optical power meters with the device under testDUT. The common partial area of the recess regions is designed in such away that the positioning apparatus PA can easily access the device undertest. Therefore, the common partial area of the recess region's RRextends to a location adjacent to the device under test DUT.

The positioning apparatus PA can, for instance, comprise a movablecantilever arm, which can easily couple the optical guides, for exampleoptical fiber OF cables connected thereto, to the device under test DUTin a reliable way, due to the freedom of movement available to it in theopen space defined by the common partial area of the segments PTS, PCS.

In FIG. 2 , a cross-sectional view of the test fixture setup accordingto the embodiment of FIG. 1 is shown. To increase the intelligibility,the individual elements/parts of the test fixture setup—with theexception of the coaxial connector—are shown in an over-simplified form.As can be clearly deduced from FIG. 2 with reference to FIG. 1 , thepogo tower 160 serves as an interface between the probe card 100 and thewafer probe interface 190. The probe card 100 is connectable to thedevice under test DUT. The wafer probe interface 190 is designedaccording to specifics of the automatic test equipmentplatform/manufacturer. The probe card 100, pogo tower 160, as well asthe wafer probe interface 190 are fixed firmly to one another, forexample with screws, in order to ensure a secure connection/contactbetween the different contacting elements, which in the presentembodiment of FIG. 2 are mainly pogo pins, e.g., 165, and coaxialconnectors 120, 175. The pogo pins PP are grouped in different segments101-104 and 161-164 respectively. Along with the pogo pins 165, othercontacts like power supplies contacts 170 can be grouped together in thedifferent segments. The segments are arranged and designed such thatsegments 101-104 of the probe card 100, as well as segments 161-164 ofthe pogo tower 160 and segments of the wafer probe interface 190 can bealigned complementary to each other. Guiding means—not shown—can befurther provided for exact alignment to each other. In the embodimentaccording to FIG. 2 , one segment accommodates the coaxial connectors175. In order to ensure a secure connection with the probe card 100, thecoaxial connectors 175 are combined in a socket slot 210 in one of thepogo tower segments 161-164 of the pogo tower 160. The socket slot 210is configured for blindly mating the coaxial connectors with acorresponding port with one or more coaxial connectors on the probe card100. According to the embodiment in FIG. 2 , high-frequency signalsand/or high-speed digital signals, which are transferred by the coaxialconnectors 175, are forwarded to the measuring instruments, for example,high-frequency instruments via coaxial cables and vice versa. Thehigh-frequency instruments can be a part of the automatic test equipmentor independent modules that can be connected to the coaxialconnectors/coaxial cables. In the present embodiment, the coaxial cablesof the coaxial connectors 175 are routed via the pogo tower 160 throughthe wafer probe interface 190 to an automatic test equipment ATE.

FIG. 3 shows a top view of a pogo tower 160 with the wafer probeinterface 190 attached to it. According to the embodiment shown in FIG.3 , three of the pogo tower segments 161, 162, 163 are equipable withpogo pins PP for low-frequency signals which are configured to contact aplurality of contact pads of a probe card—not shown. The pogo pins PP ofthe pogo tower segments 161, 162, 163 act as an interconnect forlow-frequency signals and power supply for the device under test DUT. Afourth segment 164 of the pogo tower 160 is provided with a socket slot210 therein comprising coaxial cables with coaxial connectors 175attached thereto. The coaxial connectors 175 are configured to transmithigh-frequency signals and/or high-speed digital signals fromhigh-frequency instruments to a probe card, e.g., probe card 100 (FIG. 1)—not shown—which is connectable to the socket slot 210 of the pogotower 160, hence acting as an interconnection for high-frequencysignals. According to the embodiment shown in FIG. 3 the pogo tower 160as well as the wafer probe interface 190 have a recess region 180 whichextend into an area of about a semicircle. The recess region 180 allowsfor accommodation of a positioning apparatus PA for establishing anoptical coupling between one or more optical in instruments and thedevice under test DUT over one or more optical guides, for exampleoptical fiber OF cables. The recess region 180 can be considered as asilicon/photonic interconnect for the device under test DUT. The recessregion 180 according to other embodiments—not shown—may have a shapedifferent from that of a semicircle.

FIG. 4 shows a bottom view of the pogo tower 160 with a connected waferprobe interface 190 according to the embodiment shown in FIG. 3 . Onlyone segment 162 of the three pogo tower segments 161, 162, 163configured for the reception of pogo pins PP contains pogo pins PP init, while the other two segments 161, 163 are not being used in thepresent embodiment. The fourth pogo tower segment 164 according to theembodiment shown in FIG. 3 contains the socket slot 210 thereincomprising the coaxial cables with the coaxial connectors 175 attachedthereto. The socket slot 210 according to the embodiment has a matingcoupling connector allowing a secure fixation of the coaxial connectors175 to a corresponding coupler 510 of a probe card 100—see FIG. 5 . Onemain advantage of such a plug-in connection is that it can be guided andheld firmly. Furthermore, a positioning and correct arrangement of thepogo tower 160 relative to the wafer probe interface 190 and probe card100 attached thereto can be realized by utilizing guide grooves, forexample aligning guide grooves on the edge of the pogo tower 160 withguide grooves of the wafer probe interface 190.

FIG. 5 shows a coupler for coaxial connectors 510 which is configured tomate with the corresponding contacts of the socket slot 210 (FIG. 2 ) ofthe pogo tower 160 to ensure a secure connection with/to the coaxialconnectors 175 (FIG. 2 ). The coupler is encased in a metal frame andhas a positioning aid 520 which ensures correct alignment of the coaxialconnectors 175 of the socket slot 210 of the pogo tower 160 whenconnected to the coupler for coaxial connectors 120 of the probe card100, which are comprised in the interface IF of the probe card 100.

FIGS. 6 and 7 show in a perspective view an implementation of ahigh-volume production silicon photonics test cell using a wafer probeinterface 190 and a pogo tower 160 according to the embodiments shown inFIGS. 1 to 5 . The embodiment according to FIGS. 6 and 7 can be regardedas a wafer prober with probe card auto-loading having low-speedsignaling components which are situated in the pogo tower segments 161,162, 163 having pogo pins PP and one or more power supplies PSconfigured to be coupled to the device under test DUT. Above that, aplurality of coaxial connectors 175 are provided, which are concentratedin a socket slot 210 having a metal frame and which is arranged in anadditional segment 161 of the pogo tower 160 and/or wafer probeinterface 190 to allow high-speed signaling connections. The embodimentof the high-volume production silicon photonics test cell comprises apositioning apparatus 610 for establishing an optical coupling betweenone or more optical instruments and the device under test DUT via one ormore optical guides, for example optical fiber cables 620. Thepositioning apparatus 610 according to the embodiment of FIGS. 6 and 7is designed as a cantilever arm, which can be moved in a recess region180 in which the positioning apparatus 610 is received. According toFIGS. 6 and 7 the coaxial connectors 175 of the coaxial cables of thesocket slot 210 protrude from the pogo tower 160 and/or the wafer probeinterface 190 in order to be connectable to high-frequency instruments.The high-frequency instruments—not shown—can be extern modularlyattachable instruments or instruments included in the silicon photonictest cell or automatic test equipment, respectively. Since the waferprobe interface 190 and/or the pogo tower 160 are normally applicationindependent and designed by an automatic test equipment manufacturer,they can be added, exchanged/replaced and adapted to a specific siliconphotonics test cell while increasing the flexibility in use.

In another embodiment—not shown—the coaxial cables of the coaxialconnectors CCPT are led from the PT, for example sideways, directly tomodules of external measuring/testing devices. This option/solutionensures that legacy automatic test equipment or test cells can still beused and/or upgraded.

On the basis of the above-described arrangement of the differentsegments of the probe card 100 and the—thereto—connectable pogo tower160, the automatic test equipment appareled with it can test and/ormeasure devices under test DUT being a silicon photonics device orconventional semiconductor integrated circuits as well as hybridsbetween a silicon photonics device and a conventional semiconductorintegrated circuit. Automatic test equipment using the above-describedarrangement can be configured to test one or more components of thedevice under test DUT, i.e., one or more low-speed signaling componentsand/or one or more high-speed signaling components, insequential/successive mode. Alternatively, or in addition thereto, theabove-described automatic test equipment can be operated to test one ormore components of the device under test DUT, i.e., one or morelow-speed signaling components and/or one or more high-speed signalingcomponents in the simultaneous mode, which considerably increases andimproves the application possibilities of the automatic test equipmentequipped with the above-described arrangement/test fixture setup.

An alternative embodiment for a wafer probing test fixture design—notshown—is to connect the probe card PC interface IF directly to the testfixture comprising only a probe card PC. Such a probing setup allows thedirect coupling/docking of the automatic test equipment to the deviceunder test DUT, bypassing the wafer probe interface WPI printed circuitboard and the pogo tower PT as shown in FIG. 1 . Thereby, signalperformance can be improved and allow high-frequency signaling up to 28GHz or more. Such a solution can be envisaged when a silicon photonicscoupling can be easily performed, such that no extra space/cutout in theprobe card is needed for a photonics fiber array positioner to move.Above that, the use of standardized automatic test equipment, or ratherstandardized automatic test equipment interfaces IF, allows theapplication of interchangeable instruments modules, therefore, providinga greater flexibility in use, easier customization, and expandability.

With the above described solution/integration of coaxial connectors CCPTand/or CCPC high-speed/high-frequency pins of a silicon photonicsintegrated circuit or hybrids thereof can easily be measured and/ortested. Above that, the described solution is fully compatible with astandard production pogo tower PT whereby the versatility in use isincreased.

Although some aspects have been described in the context of anapparatus, it is clear that these aspects also represent a descriptionof the corresponding method, where a block or device corresponds to amethod step or a feature of a method step. Analogously, aspectsdescribed in the context of a method step also represent a descriptionof a corresponding block or item or feature of a correspondingapparatus.

The above-described embodiments are merely illustrative for theprinciples of the present invention. It is understood that modificationsand variations of the arrangements and the details described herein willbe apparent to others skilled in the art. It is the intent, therefore,to be limited only by the scope of the impending patent claims and notby the specific details presented by way of description and explanationof the embodiments herein.

While the above description contains many specificities, these shouldnot be construed as limitations on the scope, but rather as anexemplification of one [or several] embodiment(s) thereof. Many othervariations are possible.

REFERENCES

CCPC coaxial connectors

CCPT coaxial connectors

DUT device under test

IF interface

OF optical fiber

PA positioning apparatus

PC probe card

PCS the probe card segments

PH probe head

PP pogo pins

PS power supply

PT pogo tower

PTS pogo tower segments

RR recess region

SS socket slot with coaxial connectors

WPI wafer probe interface

What is claimed is:
 1. An automated test equipment apparatus configuredto test a device under test, wherein the device under test utilizes alow-frequency signal and a high-frequency signal, the automated testequipment apparatus comprising: a probe card configured to contact thedevice under test, wherein the probe card comprises a coaxial connectorand a plurality of contact pads; a pogo tower configured to couple thecoaxial connector and the plurality of contact pads to a wafer probeinterface; a first test instrument coupled to the coaxial connector andconfigured to receive the high-frequency signal; a second testinstrument coupled to at least one of the plurality of contact pads andconfigured to receive the low-frequency signal; a third test instrumentfor optical testing of the device under test; and a positioningapparatus configured to establish an optical coupling between the thirdtest instrument and the device under test.
 2. The automated testequipment apparatus according to claim 1 further comprising a waferprobe interface configured to couple the first, second, and third testequipment to the pogo tower, wherein each of the wafer probe interface,the pogo tower, and the probe card respectively comprise a recessregion, and wherein the recess regions are configured to align with eachother at least in a common partial area, whereby the recess regionsenable the positioning apparatus to be disposed in a space defined bythe common partial areas.
 3. The automated test equipment apparatusaccording to claim 2, wherein the common partial area of the recessregions extends at least to a location adjacent to the device undertest.
 4. The automated test equipment apparatus according to claim 2,wherein the positioning apparatus comprises a movable cantilever arm. 5.The automated test equipment apparatus according to claim 4, wherein themovable cantilever arm extends to a location adjacent to the deviceunder test.
 6. The automated test equipment apparatus according to claim2, wherein the wafer probe interface comprises a void located in aregion facing the pogo tower, and wherein the void is configured forpassing a coaxial cable, coupled to the coaxial connector, through thewafer probe interface to the first test instrument.
 7. The automatedtest equipment apparatus according to claim 6, wherein coaxial connectorand the coaxial cable are located on a side of the probe card facing thewafer probe interface.
 8. The automated test equipment apparatusaccording to claim 2, comprising two modes of operation: a first mode ofoperation configured to test a plurality of components of the deviceunder test sequentially; and a second mode of operation configured totest the plurality of components of the device under testsimultaneously.
 9. The automated test equipment apparatus according toclaim 1, wherein the high-frequency signal is characterized as having afrequency of at least 25 GHz.
 10. The automated test equipment apparatusaccording to claim 1, wherein said device under test comprises aphotonics device.
 11. The automated test equipment apparatus accordinglyto claim 1, wherein said probe card further comprises: a probe headdisposed on a first side of a body of said probe card.
 12. The automatedtest equipment apparatus accordingly to claim 11, wherein said probecard further comprises: a first plurality of contact pads disposed on asecond side said body of said probe card and coupled to said probe headand electrically configured to couple to an interface assembly.
 13. Theautomated test equipment apparatus accordingly to claim 1, wherein saidcoaxial connector is operable to mate with a mating coaxial connector ofan interface assembly.
 14. The automated test equipment apparatusaccordingly to claim 1, wherein said coaxial connector is configured tocouple a signal of at least 25 GHz.
 15. The automated test equipmentapparatus accordingly to claim 1, wherein said probe card comprises asemi-circular void.
 16. The automated test equipment apparatusaccordingly to claim 1, wherein said probe card comprises a voidconfigured as for silicon/photonic interconnection to the device undertest.
 17. The automated test equipment apparatus accordingly to claim 1,wherein said probe card is configured to provide clearance for thepositioning apparatus.
 18. The automated test equipment apparatusaccordingly to claim 1, wherein said probe card is configured to pass aplurality of optical cables coupled to said device under test through avoid in said probe card.
 19. The automated test equipment apparatusaccordingly to claim 1, wherein said pogo tower comprises: a pluralityof pogo tower segments, comprising: a first tower segment of saidplurality of pogo tower segments, said first tower segment comprising aplurality of pogo pins configured to couple a pad of the probe card to awafer probe interface, and wherein a second tower segment of saidplurality of pogo tower segments, said second tower segment comprising acoaxial connector configured to couple to a mating coaxial connector ofthe probe card; and a coaxial cable configured to couple the matingcoaxial connector to a test instrument separate from the pogo tower. 20.The automated test equipment apparatus accordingly to claim 1, whereinsaid pogo tower comprises: a first pogo tower segment comprising pogopins configured for coupling power supply voltages to the probe card; asecond pogo tower segment comprising pogo pins configured for couplinglow-frequency signals to the probe card; and a third pogo tower segmentcomprising pogo pins configured for coaxially coupling high-frequencysignals to the probe card.